The present invention relates generally to improvements in implements for use in the cutting of corrugated tubing, and more particularly to a rotary blade spacer for a cutting implement of a variety which includes a rotary cutting blade, the blade spacer being configured to be received between the corrugations of the tubing for the centering of the blade therewithin.
Corrugated tubing, often fabricated of stainless steel, copper, or the like and jacketed with a plastic material, is commonly employed in residential or commercial building constructions as a transitional fluid conduit extending between an appliance or other machine and a rigid auxiliary line, pipe, or other connection of a fuel source which typically is natural gas, propane, or the like. The flexibility of such tubing facilitates the alignment of couplings and other connections, and also accommodates limited movement of the appliance or machine with respect to the rigid connection of the fuel source.
More recently, tubing of such type has been proposed as a substitute for traditional hard, i.e., inflexible, steel or iron "black" pipe in gas line applications for residential and commercial construction. Again, the flexibility of the tubing facilitates its installation through walls, ceilings, and floors and, especially, the alignment of the tubing connections. Such tubing, moreover, is lightweight, easy to carry, requires no threading or heavy equipment therefor, allows the use of fewer fitting connections, and exhibits less leak potential than conventional, hard piping. Corrugated tubing of the type herein involved additionally is used in other fluid transport applications such as in air conditioning, hydraulics, and general plumbing, and also as conduit for electrical applications. Tubing manufacturers include: Parflex Division of Parker-Hannifin Corp., Ravenna, Ohio.; Titeflex Corp., Springfield, Mass.; OmegaFlex, Inc., Exton, Pa.; Wardflex Blossburg, Pa.; Tru-Flex Metal Hose Corp., Howell, Mich.; and Flex-Pression Ltd., St. Laurent, Quebec, Canada.
It is common practice to cut or otherwise section corrugated tubing to length with a conventional pipe or tubing cutter of a hand-operable variety. Cutters of such type, a representative one of which is shown at 10 in FIG. 1, have long been known in the pipe cutting art and typically involve an arrangement which includes a C-shaped frame, 12. As may be seen in FIG. 1, a generally disc-shaped cutting blade, 14, is rotatably journalled on an axle, 16, mounted at a first end, 18, of the frame 12. A roller, 20, is disposed in opposition to blade 14 as rotatably mounted on a carriage, 22. Carriage 22, in turn, is slidably movably mounted on the frame 12 intermediate a second end, 24, thereof and blade 16. A pressure screw, 26, is threadably received through a bore formed within the second end 24 of frame 12 as operably coupled at one end in a force transmitting relationship with carriage 22 for advancing roller 20 toward blade 14. A knob or other handle, 28, is provided at the other end of screw 26 for the hand-operated rotation thereof controlling the advancement of carriage 22 along frame 12.
With a length of tubing, 30, disposed and supported intermediate blade 14 and roller 20, cutter 10 may be revolved radially circumferentially about the tubing within a plane, represented by line 32, perpendicular to the longitudinal axis, 34, of the tubing 30. As the cutter 10 is revolved and with advancement force being continuously applied to carriage 22 and roller 20 via the rotation of screw 26, the wall of the tubing 30 is cut successively deeper with each revolution of the cutter by the rotation of the blade along the tubing surface. Tubing cutters of this type are further described in U.S. Pat. Nos. 294,339; 1,833,980; and 3,376,638, and are manufactured commercially by Reed Manufacturing, Erie, Pa., Rigid Tool, Cleveland, Ohio., and Stride Co., Ellicottville, N.Y.
Other tubing and pipe cutters utilizing rotary cutting wheels are described in U.S. Pat. Nos. 1,737,889; 4,307,512; 4,402,136; 5,230,150; 5,461,955; and 5,581,886. Other cutters specifically adapted for cutting corrugated tubing are described in U.S. Pat. Nos. 4,078,304 and 4,063,355. These cutters involve a saddle-arrangement of a frame or ring formed of a hinged pair of semi-circular members which may be clamped and rotated circumferentially about the tubing. One or more rotary blades are carried by the frame for the cutting of the tubing wall.
Further with respect to cutters for corrugated tubing, and as may be seen in FIG. 1 for the representative cutter 10, the above-described conventional C-clamp devices have been modified to include a roller 20 which is profiled as having one or more circumferentially ridges, one of which is designated at 36, each configured to be received within a corresponding corrugation root, 38, of the tubing. Despite that modification, however, it has been observed in the preparation of the terminated end of the tubing for a flared connection with a fitting that the cut produced by tubing cutters of conventional design can sometimes be irregular. In this regard, and as is illustrated in the enlarged view of cutter 10 depicted in FIG. 2, any axial movement, represented by line 39, of blade 14 within the corrugation root 38 can result in an off-axis cut. Such movement may be caused by any number of factors, but typically is the result of a loose-fitting blade, a variation in the pitch of the tubing corrugations which effects a misalignment of the roller, or the operator failing to properly align the cutting blade within the center of the corrugation. The off-axis cut may produce an incomplete flare or otherwise may deleteriously affect the flaring of the tubing end. Depending upon the fitting which is employed, an incomplete flare may prevent the complete seating of the tubing end with the fitting which is necessary to achieve a fluid-tight seal.
As the use of corrugated tubing in gas line and other fluid transfer applications continues to increase, it will be appreciated that further improvements in the design of cutting implements therefor would be well-received by both industry and consumers alike. Preferred improvements would speed and simplify the cutting of the tubing while assuring that a straight cut is obtained which facilitates subsequent flaring operations and minimizes the potential for leaks and the like.